1. Field of the Invention
This invention relates generally to a warning device, particularly to a warning device for preventing child from being lost comprising a distance-adjustable high frequency host transceiver and a plurality of associated high frequency slave transceivers, wherein the host transceiver and each slave transceiver can proceed bi-directional page or response with its counterpart.
2. Description of the Prior Art
"Prevention is better than cure" seems applicable by changing it into "Prevention is better than search" in dealing with child's security problem. It is undoubtedly a severe and beyond compensable disaster to a family when a child was lost, and the cloudy family will find no joy in daily living until the child is found back. This is especially true in recent days as a family usually raises only one or two children basing on eugenics concept. On the basis of demand, there are various equipments or devices for preventing child from being lost presented in the market.
One of the devices to be cited has been disclosed in Taiwan with patent No. 300659 (abbrev. as "the patent cited" hereinafter), which is characterized in comprising a host device carried by an adult and a slave device disposed in a personal item or on a child. When the slave device departs from the host device beyond a preset security distance, the latter will alarm to warn the carrier and it can be reset for another alarm when the former reenter the security scope for easy searching. As the patent cited has been developed on the basis of personal items, it is not equally suitable to a child who may go along with his or her parents to different places and under different situations, for example, to a market jammed with people. In case the security range cannot be adjusted within 2 meters, the child may get lost in a winking of an eye. Or, when the family goes out to a park, the security range is still within 2 meters, the mother can only sit aside her child instead of resting on a farther bench.
Moreover, the patent cited is applied on paired basis, namely, one host device to one slave device that will obviously entails more expense on the parents if they have several children.
In view of abovesaid demerits, after years of constant effort in research, the inventor of this invention has consequently developed and proposed an improved warning device pertaining to the subject matter.